The cell surface molecules that participate in gamete recognition and teratocarcinoma cell adhesion are being explored. Results show that these cells display high levels of surface galctosyltransferase activity towards N-acetyl-glucosamine (NAcglc). Experiments will test two related hypotheses. First, using in vitro fertilization as an assay, we will determine whether sperm recognize and bind the egg surface via galactosyltransferase binding to egg NAcglc residues. Similar assays will biochemically analyze the in vitro fertilizing capabilities of segregation-distorting t-bearing sperm. Second, the adhesive role of F9 cell surface galactosyltransferase binding to NAcglc residues on adjacent cells will be examined. The NAcglc-containing galactosyltransferase acceptors on sperm, eggs and F9 cells will be characterized. Preliminary results suggest some of them to be similar, if not identical, to the F9 antigen. The potential inhibitory effects of sugar nucleotides, solubilized galactosyl acceptors and F9 antigen will be determined in assays of in vitro fertilization and intercellular adhesion.